Safety switch



- K. B. PINKARD ETAL SAFETY SWITCH Filed June 30, 1955 Dec. 24, 1957 I N VEN TORJ' ATTORNEYS United States Patent SAFETY SWITCH Kathryn Beyer Pinkard and Edwin A. Quinn, New Orleans, La.

Application June 30, 1955, Serial No. 519,034

2 Claims. (Cl. 200-142) This invention relates to air conditioning equipment in which a safety switch is incorporated in a motor circuit wherein the circuit is of the closed type and in which a fusible element retains a switch, such as a Mercoid switch, in the closed position, and in particular, a circuit breaker including an actuating lever extended from a conventional switch housing suspended by a bracket from a roof rafter, wall, or the like, wherein the lever is retained in the position of holding the switch closed 'with a fusible element and is adapted to be snapped to open the switch by a spring upon fusing of said element.

The purpose of this invention is to provide means for mounting both a spring and a fusible element between a switch lever and a stud on a switch housing whereby the fusible element holds the switch lever in the position of closing the switch and the spring snaps the lever to open the switch when the temperature of air or other fluid around the switch reaches a predetermined degree wherein the fusible element melts.

With the conventional type of Mercoid switch used in air conditioning equipment, and the like, a fusible element, connected to the actuating lever of the switch extends from one end of the switch housing and a spring for actuating the switch upon fusing of the element extends from the opposite end thereby requiring anchoring elements extended from both ends of the switch box or housing. In some installations, and particularly in close quarters, it is very difficult to connect the extended ends of the fusible element and spring to anchoring means. With this thought in mind, this invention contemplates a housing for a switch, such as a Mercoid switch, wherein a stud is added to the housing at a point spaced from the point from which the switch actuating lever extends and wherein both a spring and fusible element are positioned between the stud and lever so that the fusible element provides a spreader acting against the spring and retaining the lever in the position in which the switch is closed until the temperature around the fusible element is sufiicient to melt the element.

The object of this invention is, therefore, to provide means for retaining an operating lever of a switch in the closed position whereby the lever is held by a fusible element and also wherein the lever is adapted to be snapped to a position for opening the switch by a spring upon fusing of the element.

Another object of the invention is to provide an improvement in mounting elements of switches, such as Mercoid switches, wherein an element for urging the operating lever of the switch from the closed to the open position and also the element for retaining the lever in the closed position are positioned at the same side of the switch housing.

A further object of the invention is to provide means for mounting a fusible element on a Mercoid switch with out extending the fusible element beyond the switch housing in which the device is of a simple and economical construction.

With these and other objects and advantages in view, the

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invention embodies a switch, such as a Mercoid switch, mounted in a housing suspended from a bracket and having a lever extended therefrom through the housing and a stud extended from the side of the housing from which the lever extends with both a spring and a fusible element extended between the stud and lever and with ends of both elements connected to the stud and lever whereby the spring urges the lever toward the stud and the fusible element holds the lever against the action of the spring.

Other features and advantages of the invention will appear from the following description, taken in connection with the drawing, wherein:

Figure 1 is a side elevational view illustrating the use of the improved switch of this invention showing the switch on the side of a roof rafter.

Figure 2 is a longitudinal section through the switch housing, taken on line 2-2 of Figure l, with the parts shown on an enlarged scale and with the switch casing, actuating lever thereof, a mounting stud, a spring, and a fusible element shown in elevation.

Figure 3 is a view looking upwardly toward the under surface of the switch housing with the parts as shown in Figure 2.

Figure 4 is a longitudinal section through a switch box or housing, similar to that shown in Figure 2, illustrating a modification wherein the stem of a conventional switch is retained in a position wherein the switch is closed with a fusible element connected to the stem and mounted on a stud positioned in the face plate of the switch housing.

Figure 5 is a view looking upwardly toward the under surface of the switch box shown in Figure 4.

Referring now to the drawing, wherein like reference characters denote corresponding parts, the improved safety switch of this invention, particularly as illustrated in Figures 1, 2 and 3, includes a switch actuating lever 10, a switch 11 from which the lever 10 extends, an outlet box or housing 12 having a face plate 13, a stud 14 secured by lock nuts 15 and 16 in the face plate 13 of the housing, a spring 17, one end of which is anchored to the stud and the other connected to the lever 10, a fusible element 18 also positioned with one end anchored to the stud and the other connected to the switch lever 10, and a supporting bracket having a vertically disposed leg 19 and a horizontally disposed arm 20 on the under surface of which the outlet box or switch housing is positioned.

The switch lever 10 extends from the switch 11 through a slot 21 in the face plate or base 13 of the housing 12 and the extended end of the lever is provided with an opening 22 in which an end 23 of the spring 17 is connected and an opening 24 in which an end 25 of the fusible element 18 is connected. An opposite end 26 of the element 18 is anchored to the stud 14 and an opposite end 27 of the spring 17 is also anchored to the stud. The stud is provided with a head 28 and an opposite end 29 is threaded to receive the lock nuts 15 and 16 whereby the stud is secured in an opening in the base or face plate 13 of the housing.

The housing 12 is provided with flanges 30 and 31 which extend from end walls 32 and 33, respectively, and the housing is secured to the arm 20 of the bracket with bolts 34 which extend through the flanges 30 and 31 and also through the arm 20. The bolts are provided with lock nuts 35.

The switch 11 is provided with terminals 36 and 37 from which wires 38 and 39 extend, the wire 38 extend ing through an opening 40 in the end wall 32 and the wire 39 through an opening 41 in the end wall 33. The wires are connected in a circuit of air conditioning equipment or in circuits for other electrical services or appliances.

A supporting bracket is adapted to be mounted on a roof rafter, as indicated by the numeral 42, or on the surface of a wall or the like and with the parts, particularly as illustrated in Figures 2 and 3, the improved safety switch maybe positioned horizontally or vertically as may be desired. With the parts, as illustrated in Figure 2, the vertically disposed leg 19 of the supporting bracket is secured to the rafter 4-2 with screws 43 and it will be understood that the bracket may be retained in position by other suitable means.

In the design illustrated in Figures 4 and 5, a fusible element secured to the lower end of a post or stud 51 by a collar 52 which holds the flange 53 of the element against a head 54 is provided with an opening 55 through which a lower end 56 of a stem 57 of a switch 558 extends and upon fusing of the element St the spring of the switch snaps the stem 57 to a released position wherein a circuit through the switch is broken.

The stem '57 of the switch shown in Figure 4 extends through a threaded nipple 59 which is secured in a face plate 60 by lock nuts 61 and the face plate is secured to flanges 62 of a housing 63 with screws 64. The stud or post 51 is mounted in the face plate 60 with lock nuts 65 and so threaded on an end 67 of the stud 51 and the housing 63 is secured to a horizontally disposed arm 68 of a supporting bracket having a vertically disposed leg 69 with bolts 76. The supporting bracket is secured to a wall or rafter, as indicated by the numeral 71, with fasteners, such as the screws 72.

The switch 58 is provided with terminals 73 and 74 to which wires 75 and 76, respectively, are connected and the wires extend through openings 77 and 78 in end walls of the housing.

With the switch control elements positioned as illustrated in Figures 2 or 4, the fusible element is extended from the side of the switch from which the switch lever extends and with the addition of the stud forming the anchoring post all elements are nested in a compact assembly thereby facilitating the installation of switches of this type and obviating the necessity of providing anchoring posts spaced from the switch box or housing. The fusible element provides means for retaining the switch lever in a position wherein the switch is closed and upon fusing of said element a spring incorporated in the switch or connected between the switch lever and the anchoring post or stud snaps the switch to the open position.

It will be understood that modifications, within the scope of the appended claims, may be made in the design and arrangement of the parts without departing from the spirit of the invention.

What is claimed is:

1. Tu a safety device, the combination which comprises a conventional switch, a switch lever extended from the switch, a bracket for mounting the switch on a beam, rafter, or the like, a rectangular-shaped housing in which the switch is positioned, an anchoring stud mounted on the housing and spaced from the switch lever, and a fusible element positioned with one end connected to the switch lever and the other to the anchoring stud for retaining the switch lever in such a position that the switch is closed and a spring positioned in tension and mounted between the anchoring stud and switch lever wherein upon fusing of said fusible element the switch lever is by the spring actuated to open the switch.

2. In a circuit breaker, the combination which comprises an outlet box, an L-shaped bracket having a vertically disposed leg and a horizontally disposed arm positioned with the outlet box suspended from the arm, a conventional switch in the outlet box, a switch lever extended from the outlet box and connected to the switch, a stud mounted in the outlet box and extended therefrom, a fusible element mounted on the stud and attached to the switch lever, said fusible element being positioned to retain the switch lever in such a position that the switch is closed and wherein upon fusing of said fusible element the switch lever is released so that the switch lever is free to be actuated to open the switch.

References Cited in the file of this patent UNITED STATES PATENTS 1,380,493 Nissen June 7, 1921 1,677,692 Stokes July 17, 1928 2,085,386 Phillips et a1. June 29, 1937 2,354,111 Gardenhour July 18, 1944 

